1. Field of the Invention
The invention relates to an improvement to a sewing machine. More particularly, the invention relates to an improvement that allows certain materials to be controlled and fed into the sewing mechanism of a sewing machine in a hands-free manner.
2. Description of the Related Technology
The heart of the basic sewing machine is referred to herein as the "sewing mechanism", and typically contains an upper and lower part. The upper part contains a needle, a source of thread for the needle, and a foot which acts to hold the material down. The lower part contains a flat base, a secondary source of thread called a bobbin, and a set of movable gripping teeth. In operation, the materials being sewn pass between the upper and lower parts. The materials lay on the top surface of the base, are held flat against the base by the foot, and are moved forward by the action of the teeth. Interaction between the needle and the bobbin sews the fabric together at a location directly beneath the foot. This basic process has remained relatively constant since the sewing machine was invented many years ago. However, a great many improvements have been developed which allow specialized functions to be performed. These improvements generally permit such functions to be performed automatically by the machine rather than depending on the skill of the operator to perform them. Examples of such improvements are the capability for making button holes, for sewing specific types of seams, and for sewing decorative applique designs on the material.
One area which has not benefitted from such automation, however, is the attachment of elastic to predominantly non-elastic materials. For such an attachment to work properly, the elastic must be prestretched before being sewn to the material and it must remain stretched as it is being sewn. Once the elastic has been sewn and released, it returns to its normal non-stretched configuration. The result is an area of material, such as the waistband of a dress, which is normally in a "gathered" configuration but can be stretched to a larger dimension. The extra gathered fabric allows the normally non-stretchable material to effectively be stretched, while the tension in the stretched elastic provides the proper force to hold the article of clothing snugly in place.
In a typical sewing machine, the operator must manually hold the elastic in a stretched position by hand while feeding it and the fabric into the sewing mechanism. Since the operator must accurately guide the fabric and the elastic while simultaneously maintaining the proper tension on the elastic, the resulting operation is awkward and requires a great deal of skill on the part of the operator. If other materials are simultaneously being sewn into the same area, this just compounds the problem. What is needed is a device that will prestretch the elastic as it is being sewn without requiring any manual intervention by the operator.
In a related area, sewing machine operators sometimes wish to sew multiple strips of linear material, such as elastic, ribbons, strips of lace, etc., onto the same area of fabric at the same time, while accurately maintaining these strips of material in a particular configuration with respect to each other. This function requires the operator to manually guide these multiple strips and accurately maintain their proper position while simultaneously tending to the other manual operations that the operator must perform. These multiple manual operations require a great deal of skill on the part of the operator, and increase the chance for error. What is needed is a mechanism that will automatically guide various sizes of ribbon and other linear material into the sewing mechanism while accurately maintaining their proper positional orientation.
For widespread acceptance, the aforementioned needs should be met by a device that is inexpensive and simple to use so that it will appeal to the many people who sew in their homes on their personal sewing machines. It should also be capable of being easily retrofitted onto existing sewing machines.